Electromechanical lock



Dec. 10, 1968 J 5, KRAMASZ, JR, ET AL ELECTROMECHANICAL LOCK Filed 001;.22, 1965 2 '23 a 52' H3 |4 31/ V I l ALI I 3L 2 155],

Fig I ppppp O O O O o [M um {PE r H I. IIIIIII mmmmm Pa Inventors;Joseph G. Krumusz,dr.

Erich Koufmann Fi 2 by: Stanley 8. Lerner,

. Agent United States Patent Ofice 3,415,087. Patented Dec. 10, 19683,415,087 ELECTROMECHANICAL LOCK Joseph G. Kramasz, Jr., 3751Nortln'idge Drive, Concord, Calif. 94520, and Erich Kaufmann, 935Underhill Drive, Alamo, Calif. 94507 Filed Oct. 22, 1965, Ser. No.501,619 6 Claims. (Cl. 70-277) ABSTRACT OF THE DISCLOSUREElectromechanical lock having security of mechanical lock and in whichthe key carries code means for operating selected switches of aplurality of switches.

This invention relates to locking devices and, in particular, to anelectromechanical lock for providing authorized access to a securedarea.

It is often necessary for a number of authorized persons to have accessto a secured area. Such access may be provided by a simple lock and key.However, in many instances it is necessary not only to admit someone toa secured area, but to simultaneously activate accessory apparatus. Forexample, it may be required to keep a continuous record of the identityof persons entering an area, together with their times of entry andexit. In this case, the mechanism providing access to the area wouldalso have to activate an identification device and a print ing timeclock. Another example is that of a tank truck driver requiring accessto a central store of gasoliine. In this case, the device which unlocksthe metering pump must also activate associated apparatus which recordsthe identity of the driver and the number of gallons of gasoline he haswithdrawn from the central store.

Most conventional access systems use a punched card reader as a sourceof coded signals to activate the associated recording apparatus. Eachauthorized person has a uniquely punched card which he presents to thecard reader when he desires access to the secured area. The card readerprovides a plurality of electrical currents corresponding to thepresence or absence of holes on the card, and these currents are used toactivate the associated recording apparatus in the system.

The chief disadvantage of the punched card access system is that it isrelatively easy to fabricate a counterfeit punched card. For example, inthe case of the tank truck driver mentioned above, a non-authorizeddriver could easily obtain several blank cards (these are standardcommercial items) and randomly punch holes in them. Sooner or later hewould hit upon a winning combination that would activate the meteringpump. Not only would the non-authorized driver get free gasoline, butthe system would charge the gasoline to the account of an unsuspectingauthorized driver whose punched card happened to correspond to the holepattern punched by the counterfeiter.

The present invention provides a novel electromechanical lock whichcombines the security of a mechanical lock with the coding flexibilityof a punched card access system. Briefly, the invention comprises aplurality of electrical switches disposed in spaced relation to thecylinder of a pin tumbler lock. A special key is provided for operatingthe lock. One edge of the key (hereinafter referred to as the tumbleredge) has conventional serrations for operating the pin tumbler portionof the lock. The other edge (hereinafter referred to as the switch edge)has a plurality of lobes or notches formed into it which cooperate witha link mechanism that activates one or more of the electrical switches.The position and number of the notches on the switch edge of the key maybe varied so as to activate any desired number of switches, and hencethe lock and key combination operate as a coding device, i.e., theconducting or non-conducting state of each switch is determined by thepresence or absence of a corresponding notch or lobe on the switch edgeof the key.

The unique advantage of the present invention over conventional cardreader access devices is that it greatly reduces the possibility ofunauthorized persons gaining access to the secured area. Various lockcompanies, e.g., the Best Lock Co. of Indianapolis, Ind. will, uponrequest, register a particular lock so that duplicate keys to that lookwill only be issued on the authorization of the registrant. The keys tosuch registered locks are of a special type. They are exceedinglydiflicult for an ordinary locksmith to duplicate. Thus, unlikeconventional card readers, an access system equipped with the presentelectromechanical lock is virtually immune to tampering and counterfeitinputs.

The invention will be described with reference to the accompanyingdrawing, in which:

FIG. 1 is a diagram showing the elements of the invention in schematicform, and

FIG. 2 is a cut-away cross-sectional view of a practical embodiment ofthe invention.

Referring now to FIG. 1, there is shown a common electrical lead 11which is connected to a source of electrical power, and which branchesout into five switched leads 12, 13, 14, 15, and 16. The electricalswitches associated with leads 12, 13, 14, 15, and 16 are designated12', 13, 14', 15', and 16, respectively. These switches are opened andclosed by respective mechanical links 12", 13", 14", 15", and 16". A key18, having conventional tumbler-engaging serrations 19 on its tumbleredge 21, is provided with a number of projections 22, 23, and 24- alongits other or switch edge 26. The key is inserted into the cylinder of aconventional tumbler lock (omitted for sake of clarity) so thatserrations 19 engage and operate the lock tumblers.

In the operation of the apparatus shown in FIG. 1, rotation of key 18causes projections 22, 23, and 24 to bear against and depress links 12",13", and 16", respectively. Accordingly, switches 12', 13, and 15' areclosed, and current will flow through leadsl2, 13, and 15 via the powersupply and common lead 11. The various lead currents are connected intosubsequent logic circuitry as indicated in the drawing. Such circuitrymay comprise an AND gate having a number of inputs corresponding to thenumber of leads coming from the lock (five inputs in FIG. 1). The designof such logic circuit elements is well known in the computer art. It isto be understood that the three projections 22, 23, and 24 in thedrawing are shown only for purposes of illustration, and the actualnumber of projections may range from one to five in the case of a fiveswitch system as shown. Further, the switches shown in FIG. 1 are of thetype which require a positive pressure to place them in their conductingstate. The use of such switches dictates the use of projecting lobes onkey 18. However, the switches may alternatively be the type whichrequire the release of a pressure to place them in their conductingstate. In such case, key 18 would be provided with a plurality ofindented notches rather than projecting lobes.

The total number of combinations of open and closed switches may bedetermined by the relation:

where:

C total number of switch combinations N total number of switchesP=number of lobes (or notches) n key For example, five switches andthree lobes (as shown in FIG. 1) gives a total number of switchcombinations equal to ten Thus, ten authorized persons could each have aunique key to the lock. If there were ten switches and four lobes, thetotal number of key combinations would be 210. It is therefore apparentthat the number of switches, as well as the number of lobes or notcheson the key, can be changed to accommodate the number of personsrequiring access to the secured area.

FIG. 2 is a cut-away, cross-sectional view of a practical embodiment ofthe invention. Referring to FIG. 2, there is shown a housing 27 withinwhich a lock cylinder 28 is rotatably mounted. A plurality of laterallyopposed pivot members 29 are disposed within the housing and arepivotally mounted about pivot pins 31. A plurality of laterally opposedpush rods 32 are disposed within the housing so as to bear at one oftheir ends against pivot members 29, and at their opposite ends againsta plurality of laterally opposed electrical switches 33.

When key 18 is inserted into lock cylinder 28, serrations 19 engage thelock tumblers 20, thereby allowing cylinder 28 to rotate withinhousing27. Rotation of the key causes projections 22, 23, and 24 to bearagainst respective pivot members 29, causing them to pivot about pins31. The pivotal motion of pivot members 29 is transmitted to push rods32, thereby causing the push rods to activate switches 33. As mentionedpreviously in connection with FIG. 1, the depiction of projections orlobes on key 18 is merely for convenience in illustration. The apparatuscan just as easily be constructed using indented notches on the keyrather than projections. If notches were used, switches 33 would have tobe selected such that a pressure release would activate the switch.

The basic concept of the invention is the combination of a mechanicallocking device and corresponding key together with a plurality ofelectrical switches which are activated in a coded sequence in responseto information coded on the key. It will be appreciated that there aremany ways to embody this basic concept. For example, although theinvention has been described and shown with particular reference to amechanical lock of the pin tumbler type, there are types of mechanicallock that are suitable for use with the invention, and it is notintended to limit the invention to pin tumbler locks. In anothermodification, instead of activating the electrical switchessimultaneously (as shown in FIGS. 1 and 2), the notches on the key couldbe staggered rather than aligned so that as the key was turned theswitches would be activated at different times. The result would be anelectrical output coded in time, and such an output might be moresuitable for certain applications. A

further embodiment providing such a sequential coded output would be toprovide the key in the form of a cylinder having contact studs at spacedintervals on its surface. The mechanical unlocking function of the keyin this case could be embodied as a projection on the cylindricalsurface that would displace (and hence unlock) a correspondingprojection in the body of the lock. Yet a further modification applyingto the embodiment of FIGS. 1 and 2 would be to substitute plural contactswitches for the single throw switches shown in the drawing. Thus, aspush rods 32 were activated, they would cause to close (or open) apredetermined number of contacts in each switch. The number of contactsto be closed could easily be preset by limiting the linear travel of thepush rods, and this, in turn, would be set by the depth of the key notchor the height of the key projection.

It will be apparent that there are various ways to embody the basicconcept the invention, and it is intended to limit the scope of theinvention solely by the scope of the following claims.

We claim:

1. An electromechanical lock, comprising in combination,

(a) lock means capable of existing in locked and unlocked mechanicalstates,

(b) key means having serrations along one edge and cooperating with saidlock means to transfer said lock means between its locked and unlockedstates, said key means including coded means carried by the key means,said coded means comprising a plurality of notches and lands disposed onan edge of said key which is opposite to said first named edge, and

(c) a plurality of electrical switches operated by the coded means ofsaid key means when said lock means is in its unlocked state and adaptedto provide a plurality of electrical signals.

2. An electromechanical lock, comprising in combination,

(a) a housing,

(b) a pin tumbler lock cylinder rotatably mounted within said housing,

(c) a key having on one of its edges serrations which engage the pintumblers of said lock, and having on its opposite edge a coded sequenceof notches and lands,

(d) a plurality of electrical switches disposed within said housing, and

(e) a plurality of link members adapted to be operated by said key assaid cylinder is rotated, and means connecting said link members to saidswitches so that the switches are actuated in accordance with the codeof the notches and lands (as to convert the coded sequence of notchesand lands into corresponding activation of said switches).

3. In an electromechanical lock, a body, a barrel rotatably mounted inthe body for movement between locked and unlocked positions, a pluralityof tumblers slidably mounted in said barrel and said body for movementradially of the barrel, said barrel having a keyway extending axially ofthe keyway, a key adapted to be inserted into the keyway and having aplurality of serrations for engaging the tumblers to correctly positionthe tumblers so that the barrel can be rotated in the body from thelocked to the unlocked positions when the key is disposed in the keyway,a plurality of switches mounted on the body, coded means carried by thekey and lever means pivotally mounted on the body for each of theswitches and adapted to be engaged by the coded means carried by the keywhereby selected switch or switches of said plurality of switches areoperated upon rotation of the barrel from the locked position.

4. An electromechanical lock as in claim 3 wherein each of said switchesis a self-contained switch having an operating member yieldably urged inone direction, and wherein said lever means includes an operating rodengaging the operating member of the associated switch.

5. An electromechanical lock as in claim 4 wherein said barrel isprovided with a slot in alignment with said keyway and wherein saidcoded means carried by the key is disposed on the side of said keyopposite the side on which the serrations are provided and is accessihlethrough the slot provided in the barrel and wherein each of said levermeans includes means for engaging the coded means carried by the key.

6. An electromechanical lock as in claim 3 'Wherein said switches aredisposed on opposite sides of said body.

References Cited UNITED STATES PATENTS 1,417,715 5/1922 Bryce 70-434 5MARVIN A. CHAMPION, Primary Examiner.

EDWARD J. MCCARTHY, Assistant Examiner.

US. Cl. X.R. 70-393, 434; 200 -44

